What happens to the work done when a jnu-6* 7voidxqq veo.3 ar of orange juice is vigorously shaken?

When a hot object warms a cooler object,og3tfo- o/9xcy);io ps( v r(h does temperature flow between them? Are the temperature changfo ( i /ytsh(p)ro;9xvg co-o3es of the two objects equal?

(a) If two objects of different temperatures are placed in contacfgqw7 j1)fngr,g0tj4t wj 2(zt, will heat naturally flow from the object with higher internal energy to the object with lower internal energy? (b) Is it possible forgqfzww(gjnt2rf0 g1 )47jtj , heat to flow even if the internal energies of the two objects are the same? Explain.

In warm regions where tropical plants grow but the oziwmdmd:s7yg (*w7( temperature may drop below freezing a few times in the winter, the destruction of sensitive plants due to freezing can be reducedi(wsmd7*:d ozy7mwg ( by watering them in the evening. Explain.

The specific heat of wa)hyp3dcpt)nl /cy kc t26nus8o5x6 1kter is quite large. Explain why this fact makes water particularly good for heating systems (that is, ho x)3dkolt 6s n6p5)k2nhcc8y 1/pty cut-water radiators).

Why does water in a metal canteen stay cooler ifv s;hz :,gl5ogs.qgp8lf .d d y*5dtz/ the cloth jacket surrounding the canteen is kept moizsg.y g/gf. zhqlt ;5o*s,5d l8ddpv:st?

Explain why burns caused by steam on the skin are ofte ni/jjtje1 *;lmt: xw7n more severe than burns caused by wat1;ijnl*jmj x7e: w/tter at 100 $^{\circ} C$ .

Explain why water cools (its temperature-wwq350qf;j+w / a)m;;bub6n he5l glnbuzir drops) when it evaporates, using the concepts ofwuu6bj;blh i n+wb3z -a )gnf/q;55w;r0elq m latent heat and internal energy.

Will potatoes cook faj 3y roptksg 6g32j/dlga2l/0ster if the water is boiling faster?

Does an ordinary electric fan cool the air? Why or why not? If nz ,(cvhq wk4/-d1uxvgw 3teq)ot, why use it?

Very high in the Eart3(*z3in20ylufkgr-xx h hsx2 h’s atmosphere, the temperature can be 700 $^{\circ} C$ . Yet an animal there would freeze to death rather than roast. Explain.

Explorers on failed Arctic expeditions have survived by covering themselvia3qt /mjgc ,7ajw.o/t:*dg :x9rxv pes with snow. Why would thj,q:pmajw /r/v.:ia*x 39 xtdg7tcog ey do that?

Why is wet sand at the beach cooler to walk on trw yt7 2adm45nf8 gqu1han dry sand?

If you hear that an object has “high heat content,” does tp w+z81oni4 vchat mean that its temperature is hi81p+ nc zi4wovgh? Explain.

When hot-air furnaces are u ,tsw/7 zcsq)p/ 5ttggsed to heat a house, why is it important that there be tgqz pt/c5,s/w 7)tsg a vent for air to return to the furnace? What happens if this vent is blocked by a bookcase?

Ceiling fans are sometimes reversible, so that they drive the air down in ,vhm7jaaq- ug m59z)qone season and pull it up in another seasojm9q ahm7 u 5-z)q,vgan. Which way should you set the fan for summer? For winter?

Down sleeping bags az66c n /yqqho6nd parkas are often specified as so many inches or centimeters of loft, the actual thickness of thz/6co6qy q nh6e garment when it is fluffed up. Explain.

Microprocessor chips have a “heat sink” glued on top that looks like8+jg *t: qh (zm n gtdbn3aza2ooj-.2a a series of fins. Why is it shape-jngzo23+da*m(2g.ta 8 qhozan btj:d like that?

Sea breezes are often encountered on sunny d/m2s./duc4gvsz5zgb2l x1m c if03y nays at the shore of a large body of water. Explain in light of the fact that the temperature of the land rises more rapidly than thafmyciv2nu02dl.4 g czz3/1s/sm5 xgb t of the nearby water.

The floor of a house on a foundab 0ujnno9 4cy0tion under which the air can flow is often cooler than a floor that rests directly on the grjn u cbn90o0y4ound (such as a concrete slab foundation). Explain.

A 22 $^{\circ} C$ day is warm, while a swimming pool at $22\; ^{\circ}C$ feels cool. Why?

Explain why air temperature readings are always taken with the thermometer in th4etwl) /looo:b dr- obm5q+t)e shaqrmb :w)otdoet/+ob l5 l4-o)de.

A premature baby in an incubator can be dangerously cooled even wx0l n1/lt o.fdhen the air temperature in the in/f 0tll .ndox1cubator is warm. Explain.

Why is the liner of a th jrkrh5s1ez 7/ermos bottle silvered (Fig. 14–15), and why does it have a vacuum between its two wrzj/17ek r h5salls?

Imagine you have a wall that is( l.d 2*6zt,lxunsj p )+ovu* pq,jwtx very well insulated — it has a very high thermal resi2 ,u6sj )oltdp**ujz +xqvl p, w.n(xtstance, $R_1$ Now you place a window in the wall that has a relatively low R-value, $R_2$ What has happened to the overall R-value of the wall plus window, compared to $R_1$ and $R_2$ [Hint: The temperature difference across the wall is still the same everywhere.]

Heat loss occurs through windows by the following processes:9hdkd2gn5z7yki sk 9(s /j37jm1 xxut (1) ventilation around edges; (2) through the frame, particularly if it is metal; (3) through the glass panes; and (4) radiation. (a) For the first three, what is (are) the mechanism(s): condtghkmik31x97 dy nx7ud (5ss/kz9j2juction, convection, or radiation? (b) Heavy curtains reduce which of these heat losses? Explain in detail.

A piece of wood lying in the Sun absorbs more heat r j1skq:rp4)0,fvo,0raa tjc than a piece of shiny metal. Yet the wood feels less hot than the metal when you pic4f0rr o:s1 vaqkc0,,rp)j ajtk it up. Explain.

The Earth cools off at nigr- q*1 uujm4rv -v1:p5lafihlht much more quickly when the weather is clear than when cloudy.:mv4-rual fl -ij* 1hpq51uv r Why?

An “emergency blanketj5,mj+yxc, *o 4.vq,asnw m)cwh( in v” is a thin shiny (metal coated) plastic foil. Explain how it can help tohic o*wa+qvj s ,v x,4 m)wmn(5n,jc.y keep an immobile person warm.

Explain why cities situated by the ocean tend to have less extreme ) js:+h5f:pk9b z -yi 1wbsawvtemperatures than inland cities at th+1z w95b-s hjkf:ps:aiyvb )we same latitude.

  How much heat (in joules) is required to raise tnb5;suil:sfe 8ls,p 0- crv7e he temperature of 30.0 kg of water rsp-i70 l,e 5svuc:bn s;l fe8from 15 $^{\circ} C$ to 95 $^{\circ} C$ ?    $ \times10^{7 }\,J$

  To what temperature will 7700 J of heat o6g6lt t cilo*1 ::hejraise 3.0 kg of water that is initially at 10egj1 tc::*oio6tlh6 l.0 $^{\circ} C$ ?    $^{\circ} C$

  An average active person consumes about 2500 Cal a dawyl+l .yr16mdbd/0dp4/s r u ny.
(a) What is this in joules?   $ \times10^{7 }\,J$
(b) What is this in kilowatt-hours?    kWh
(c) Your power company charges about a dime per kilowatt-hour. How much would your energy cost per day if you bought it from the power company? Could you feed yourself on this much money per day?    dollars per day

A British thermal unit (Btu) is a unit of heat in the Bugiyb6 -; tp/+rn ol3vritish system of units. One Btu u+l-/g3 6yob; t nvpriis defined as the heat needed to raise 1 lb of water by 1 F $^{\circ} $ . Show that
1Btu = 0.252kcal=1055J

  A water heater can genecfu;iccbe3 vq9 qd 37u2m6 sd3rate $32,000\,kJ/h$ How much water can it heat from 15 $^{\circ} C$ to 50 $^{\circ} C$ per hour?    kg/h

  A small immersion heater is rated at 350 W. Estimate how long it wilhs0k8:0n 5 /wxrpxgs pl take to heat a cup of soup (assume this is 250 mL of water) fro nkx5 srw: p/ghspx080m 20$^{\circ} C$ to 60$^{\circ} C$ .    min

  How many kilocalories are generated when the brakes are used to bring a 1200-k1diyz z c78;ywhf ;wq+g car to rwdz;7qh81; fy z ci+wyest from a speed of $95\,km/h$ ?    kcal

  An automobile cooling system holds 16 L of water. How much heat does it ab4fg:9 t v47vz2uq0o ) v ea1ahwd/o dv5xljey2sorb if its tempewvv1:v q2uly)ed 44ead jo2f9o7vhg/z5a tx 0rature rises from 20$^{\circ}C $ to 90$^{\circ} C$?    $ \times10^{ 6}\,J$

  What is the specific heat of a metal substance if 135 kJ of heat is ;6npe-y ouqn9 needed to raise 5.1 kg o q 9p;y6-ounenf the metal from 18.0$^{\circ}C $ to 31.5$^{\circ} C$ ?    $J/kg\cdot\,C^{\circ} $

  Samples of copper, aluminum, and water experience the same tqfj 4f3ofbzl0-jrm ljv * f0vb+f )20aemperature rise when they absorb the same amount of hej*mqr+j-vfl3b0 0 o)f2 b fj0 lazff4vat. What is the ratio of their masses? [Hint: See Table 14–1.]$m_{Cu}$ : $m_{Al}$ : $m_{H_2O}$ =    :    :   

  A 35-g glass thermometer readklhv2 33r+0 tlzzh) t+0aum*mq x lgi3s 21.6$^{\circ} C$ before it is placed in 135 mL of water. When the water and thermometer come to equilibrium, the thermometer reads 39.2$^{\circ} C$ . What was the original temperature of the water?$T_{iH_2O}$ =    $^{\circ}C $

  What will be the equilibriwy u1ma6 h,6:ihgp/o *tg s)tqum temperature when a 245-g block of copper at 285$^{\circ}C $ is placed in a 145-g aluminum calorimeter cup containing 825 g of water at 12.0$^{\circ} C$ ? $T_{eq}$ =    $^{\circ} C$

  A hot iron horseshoe (mr p uoeu p*ex4/ht4-j0ass = $0.4\,kg$) just forged (Fig. 14–16), is dropped into 1.35 L of water in a 0.30-kg iron pot initially at 20.0$^{\circ} C$ . If the final equilibrium temperature is 25.0$^{\circ} C$, estimate the initial temperature of the hot horseshoe.    $^{\circ} C$

  A 215-g sample of a substance is heatedewvl6r-, tz 5z.q+v.o kxz3io to 330$^{\circ} C$ and then plunged into a 105-g aluminum calorimeter cup containing 165 g of water and a 17-g glass thermometer at 12.5$^{\circ} C$ . The final temperature is 35.0$^{\circ} C$ . What is the specific heat of the substance? (Assume no water boils away.)    $J/kg \cdot C^{\circ} $

  How long does it take a 750-W coffeepot to bring to a boil 0.75 L of water initin ,o/)z2rirb sally at sz2 or/bin ,r)8.0$^{\circ}C$? Assume that the part of the pot which is heated with the water is made of 360 g of aluminum, and that no water boils away. $\approx$    min (Round to the nearest integer)

  Estimate the Calorie content of 75 g of candy from thoxdex8t. 7uqjb31c nc 5i+9bbb(dk5re following measurements. A 15-g sample of the candy is allowed to dry before putting it in a bomb calorimeter. The aluminum bomb has a mass of 0.725 kg and7 1kbue3rq c t(d.i55xc b bxn8jb9+do is placed in 2.00 kg of water contained in an aluminum calorimeter cup of mass 0.624 kg. The initial temperature of the mixture is 15.0$^{\circ}C $ , and its temperature after ignition is 53.5$^{\circ} C$ .    Cal

  When a 290-g piece oc( wj( 3gk0xzhf iron at 180$^{\circ} C$ is placed in a 95-g aluminum calorimeter cup containing 250 g of glycerin at 10$^{\circ} C$ , the final temperature is observed to be 38$^{\circ}C $ . Estimate the specific heat of glycerin.    $J/kg \cdot C^{\circ} $

  The 1.20-kg head of a hammer has a speed ox x/: b;yup/ e8dn:bhwf $6.5\,m/s$ just before it strikes a nail (Fig. 14–17) and is brought to rest. Estimate the temperature rise of a 14-g iron nail generated by 10 such hammer blows done in quick succession. Assume the nail absorbs all the energy.    $C^{\circ} $

  The heat capacity, C, of an object is defined as the amount of heat needed to ra1i,sh qun)h1sd .5 snbise its temperature by )hun5s .1,1hqisns db 1 $C^{\circ} $ . Thus, to raise the temperature by $\Delta\,T$ requires heat Q given by
$Q\,=\,C\,\Delta T$
(a) Write the heat capacity C in terms of the specific heat, c, of the material.
(b) What is the heat capacity of 1.0 kg of water?    $ \times10^{3 }\,J/C^{\circ}$
(c) Of 25 kg of water?   $ \times10^{ 5}\,J/C^{\circ}$

  How much heat is needed to melt 16.50 kg of sihh9(r0nu6z0jw1ms v5r rtgo y*( hq6flver that is initially at 20$^{\circ} C$?    $ \times10^{6 }\,J$

  A 0.095-kg aluminium sphere is dropped from the roof of a 45-m-high building. w w.bmcxs(53m qe f y7o73gt6cIf 65% of the thermal energy proft7yw63c.s x ogm(w3 5bc eq7mduced when it hits the ground is absorbed by the sphere, what is its temperature increase?    $C^{\circ}$

  During exercise, a person may give off 180 kcal of heat in 30 miqzle(2gfp:y.k., t(fe f3 eko n by evaporation of water from the skin. How much water has be(g:f3e.e kz ,yf(2 t qlke.opfen lost?    kg

  If $2.80 \times10^{ 5}J$ of energy is supplied to a flask of liquid oxygen at -183$^{\circ} C$ how much oxygen can evaporate?    kg

  A 30-g ice cube at its melting point is dropped into an insulg; 4 f,vg6bqz28ndeboc6hk*aated container of l6;b fchdn4bk8q 2az,go6e g *viquid nitrogen. How much nitrogen evaporates if it is at its boiling point of 77 K and has a latent heat of vaporization of $200\,kJ/kg$ Assume for simplicity that the specific heat of ice is a constant and is equal to its value near its melting point.    kg

  A cube of ice is taken fron -d awlw113dayhz: 6fm the freezer at -8.5 $^{\circ} C$ and placed in a 95-g aluminum calorimeter filled with 310 g of water at room temperature of 20.0$^{\circ} C$. The final situation is observed to be all water at 17.0$^{\circ} C$. What was the mass of the ice cube?    $ \times10^{-3 }$ kg

  An iron boiler of mass 23c- sc/l3k o2us0 kg contains 830 kg of water at 18$^{\circ} C$. A heater supplies energy at the rate of $52,000\,kJ/h$ How long does it take for the water
(a) to reach the boiling point,$\approx$    h (Round to one decimal place)
(b) to all have changed to steam?$\approx$    h (Round to the nearest integer)

  In a hot day’s race, a bicyclist consuml bx+5qbm 7*r2/ v as47 xgygtblai/u2es 8.0 L of water over the span of four hours. Making the approximation that all of the cyclist’s energy goes into evaporating this water as sweat, how much energy in kcal did the rider use during the ride? (Since the +x27 b/v4aultyimg*g arxqb/l27 5b sefficiency of the rider is only about 20%, most of the energy consumed does go to heat, so our approximation is not far off.)    kcal

  What mass of steam atj8fo(2lwdak d3 v*4ka 100$^{\circ} C$ must be added to 1.00 kg of ice at 0$^{\circ} C$ to yield liquid water at 20$^{\circ} C$ ?    kg

  The specific heat of m/q/;f:q( vkr ngl-xzhercury is $138\,J/kg$$\cdot\,C$ Determine the latent heat of fusion of mercury using the following calorimeter data: 1.00 kg of solid Hg at its melting point of -3.9$^{\circ} C$ is placed in a 0.620-kg aluminum calorimeter with 0.400 kg of water at 12.80$^{\circ} C$ ; the resulting equilibrium temperature is 5.06$^{\circ} C$ .    $ \times10^{ 4}$ J/kg

  A 70-g bullet traveling at (-.ccf5 ck3yb rbh96 go rzvq+n yp*e,$250\,m/s$ penetrates a block of ice at 0$^{\circ} C$ and comes to rest within the ice. Assuming that the temperature of the bullet doesn’t change appreciably, how much ice is melted as a result of the collision?   g

  A 54.0-kg ice-skaterpgm79u*k.ttzp dsk* wc,/ka 4 moving at $6.4\,m/s$ glides to a stop. Assuming the ice is at 0$^{\circ} C$ and that 50% of the heat generated by friction is absorbed by the ice, how much ice melts?    g

  At a crime scene, the forensic investigator notes tha hpwt9k,(wks) t the 8.2-g lead bullet that was stopped in a doorframe apparently melted completely on impact. Assuming the bullet was fired (hks,pw wt)9kat room temperature (20$^{\circ} C$ ), what does the investigator calculate as the minimum muzzle velocity of the gun?    m/s

  One end of a 33-cm-long aluminum rod w6fe-l )53h 0by alzf0vbxgxm -ith a diameter of 2.0 cm is kept at 460$^{\circ} C$ , and the other is immersed in water at 22$^{\circ} C$ . Calculate the heat conduction rate along the rod.    W

  Calculate the rate of heat flow by c/vsqnl*.1j kjonduction in Example 14–10, assuming that there are strong gusty windljv1/q*. jnsks and the external temperature is -5$^{\circ} C$   $ \times10^{4 }$ W

  (a) How much power is radiated by a tungsten sr,evc 1aj zdd(q;xh5(m pk3p,phere (emissivity $e\,=\,0.35$) of radius 22 cm at a temperature of 25$^{\circ} C$ ?    W
(b) If the sphere is enclosed in a room whose walls are kept at -5$^{\circ} C$ what is the net flow rate of energy out of the sphere?    W

  Heat conduction to skin. Suppose 200 W of heat flows by conductiovpwvu*u oi3z(n / l-;xn from the blood capillaries beneath the skin t *3woi-zuulx;(pv/ vno the body’s surface area of $1.5\,m^2$ If the temperature difference is 0.50 $C^{\circ} $ , estimate the average distance of capillaries below the skin surface.    $ \times10^{-4 }$ m

  Two rooms, each a cube 4.0 m per s8ctgw : xsy-9dide, share a 12-cm-thick brick wall. Because of a number of 100-W lightbulbs in one room,d 9t8 :xswgcy- the air is at 30$^{\circ} C$, while in the other room it is at 10$^{\circ}C $. How many of the 100-W bulbs are needed to maintain the temperature difference across the wall?    bulbs

  How long does it take the Sunyao ;gxavx6a d +/.j2r to melt a block of ice at 0$^{\circ} C$ with a flat horizontal area $1.0\,m^2$ and thickness 1.0 cm? Assume that the Sun’s rays make an angle of 30$^{\circ} $ with the vertical and that the emissivity of ice is 0.050.    h

  A copper rod and an aluminum rod of the same length and cross-sz9kc1cc 4w 3 .:k(e b.pdxkxplectional area are attached end to end (Fig. 14–18). The copper end is placed in a furnace maintained atekldxkpwb:4z.3 1cc. x (ckp9 a constant temperature of 250$^{\circ} C$. The aluminum end is placed in an ice bath held at constant temperature of 0.0$^{\circ} C$ . Calculate the temperature at the point where the two rods are joined.    $^{\circ} C$

  (a) Using the solar constant, estimate the rate at wrx se/-lb8 v:khich the whole Earth receives ener-k8sr/evb lx:gy from the Sun.    $ \times10^{17 }$W
(b) Assume the Earth radiates an equal amount back into space (that is, the Earth is in equilibrium). Then, assuming the Earth is a perfect emitter ($e\,=\,1.0$) estimate its average surface temperature.    $^{\circ} C$

  A 100-W lightbulb geno60z1-75wia n nmb6crizti8yerates 95 W of heat, which is dissipated through a glass bulb that has a radici7w1i6 yzazn-n 5rboimt 608us of 3.0 cm and is 1.0 mm thick. What is the difference in temperature between the inner and outer surfaces of the glass?   $^{\circ}C $

  Suppose the insulatin edi5sil mx1/w4 inc23,*loiu g qualities of the wall of a house come mainly from a 4.0-in. layer of brick anc1 md,nsliiii5243uew *lox /d an R-19 layer of insulation, as shown in Fig. 14–19. What is the total rate of heat loss through such a wall, if its total area is $240ft^2$ and the temperature difference across it is 12 $F^{\circ} $?    Btu/h

A double-glazed window has two panes of glass separated by an airx31yxo; rzn-btt g82on r jn.pxf)2b6 space, Fig. 14–20. (a) -nbxor2t rn23 ;.j68fgpzyt )nx1boxShow that the rate of heat flow through such a window by conduction is given by
$\frac{Q}{t}$ = $\frac{A(T_2-T_1)}{l_2/k_1+l_2/k_2+l_3/k_3}$,
where $k_1$,$k_2$ and $k_3$ are the thermal conductivities for glass, air, and glass, respectively. (b) Generalize this expression for any number of materials placed next to one another.

  Approximately how long should it take 11.0 kg ofoit.i:.c0 *p1vj t7r*jbj jub ice at 0$^{\circ}C $ to melt when it is placed in a carefully sealed Styrofoam ice chest of dimensions $25\,cm\times\,35\,cm\times\,55\,cm$ whose walls are 1.5 cm thick? Assume that the conductivity of Styrofoam is double that of air and that the outside temperature is 32$^{\circ} C$.    $ \times10^{4 }$s

  A soft-drink can con gt+blv++1y0n- bofxb tains about 0.20 kg of liquid at 5$^{\circ}C $. Drinking this liquid can actually consume some of the fat in the body, since energy is needed to warm the water to body temperature (37$^{\circ} C$). How many food Calories should the drink have so that it is in perfect balance with the heat needed to warm the liquid?    C

  If coal gives off $30\,MJ/kg$ when it is burned, how much coal would be needed to heat a house that requires $ 2.0\times10^{5 }\,MJ$ for the whole winter? Assume that 30% of the heat is lost up the chimney.    kg

  To get an idea of how much thermal energy is contained in the world’ dgwvyz1obr1s/( +i6x s oceans, estimate the heat liberated when a cube of ocean water, 1 km on each siy1b 6 dsxw1 rvzgo+(i/de, is cooled by 1 K. (Approximate the ocean water as pure water for this estimate.)    $ \times10^{ 15}\,J$

  A 15-g lead bullet is tested by firing it into a fixed block of wood with apuhna7 9:--kfegf m f3 mass of 1.03gfn: kfpue-9m-f 7ha 5 kg. The block and imbedded bullet together absorb all the heat generated. After thermal equilibrium has been reached, the system has a temperature rise measured as 0.020 $C^{\circ} $. Estimate the entering speed of the bullet.    m/s

  (a) Find the total power radiated into space by the Sunvher2gz0 p-m 6, assuming it to be a perfect emite-mp gvhr z620ter at $T\,=\,5500K$ The Sun’s radius is $7.0 \times10^{ 8}\,m$    $ \times10^{ 26}\,W$
(b) From this, determine the power per unit area arriving at the Earth, $1.5 \times10^{ 11}\,m$ away (Fig. 14–21).    $ \times10^{ 3}\,W/m^2$

  During light activity0+ li t hihlyy-)o4p;7kct3lo q(fqyes +;q1g, a 70-kg person may generate $200kcal/h$ Assuming that 20% of this goes into useful work and the other 80% is converted to heat, calculate the temperature rise of the body after 1.00 h if none of this heat were transferred to the environment.    $C^{\circ} $

  A 340-kg marble boulder rolls off the top of a cliff and falls a v67me rw9br y4y*: cpxoertical height of 140 m before striking the ground. Estimate the temperature rise of the rock if 50%brmyp c*w97:ro y64 ex of the heat generated remains in the rock.    $C^{\circ} $

  A 2.3-kg lead ball is dropped into a 2.5-L insulated pail of water initiar6)c-ssen 3peb7 bzv 4lly at eb7 pzs 4c3-)bersv6n20.0$^{\circ} C$. If the final temperature of the water–lead combination is 28.0$^{\circ} C$, what was the initial temperature of the lead ball?    $^{\circ}C $

  A mountain climber wears w9i**6l)eyji r 9tv noa goose down jacket 3.5 cm thick with total surface arevylt*o)r w6i9 9*nj eia $1.2\,m^2$ The temperature at the surface of the clothing is -20$^{\circ}C $ and at the skin is 34$^{\circ} C$. Determine the rate of heat flow by conduction through the jacket
(a) assuming it is dry and the thermal conductivity k is that of down,    W
(b) assuming the jacket is wet, so k is that of water and the jacket has matted to 0.50 cm thickness.    W

  A marathon runner has an average metabolism*ca 8ich/f8:wgm,ee i rate of about $950\,kcal/h$ during a race. If the runner has a mass of 55 kg, estimate how much water she would lose to evaporation from the skin for a race that lasts 2.5 h.    kg

  Estimate the rate at which heat can be conducted from the interiomer6rt4vy4z 4 r of the body to the surface. Assume thrtm6r4zv44 ye at the thickness of tissue is 4.0 cm, that the skin is at 34$^{\circ}C $ and the interior at 37$^{\circ}C $, and that the surface area is $1.5\,m^2$ Compare this to the measured value of about 230 W that must be dissipated by a person working lightly. This clearly shows the necessity of convective cooling by the blood.    W

  A house has well-insulated walls 17.5 cm thick (ast):l5 6fdhj2y9bfkr jsume conductivity of air) and are5jfhl yj6k r92f):dbta $410\,m^2$ a roof of wood 6.5 cm thick and area $280\,m^2$ and uncovered windows 0.65 cm thick and total area $33\,m^2$
(a) Assuming that heat is lost only by conduction, calculate the rate at which heat must be supplied to this house to maintain its inside temperature at 23$^{\circ}C $ if the outside temperature is -10$^{\circ} C$    $ \times10^{5 }$W
(b) If the house is initially at 10$^{\circ} C$, estimate how much heat must be supplied to raise the temperature to 23$^{\circ} C$ within 30 min. Assume that only the air needs to be heated and that its volume is $750\,m^3$    $ \times10^{ 8}$J
(c) If natural gas costs 0.080 dollars per kilogram and its heat of combustion is $ 5.4\times10^{7 }\,J/kg$ how much is the monthly cost to maintain the house as in part (a) for 24 h each day, assuming 90% of the heat produced is used to heat the house? Take the specific heat of air to be $0.24\,kcal/kg$$\cdot\,C$.    dollars

  A 15-g lead bullet traveling at kon aft-fw./rnyi;n5m, :o)g $220\,m/s$ passes through a thin wall and emerges at a speed of $160\,m/s$ If the bullet absorbs 50% of the heat generated, (a) what will be the temperature rise of the bullet? (b) If the bullet’s initial temperature was 20$^{\circ} C$, will any of the bullet melt, and if so, how much?    $C^{\circ} $

  A leaf of area $40\,cm^2$ and mass $ 4.5\times10^{-4 }\,kg$ directly faces the Sun on a clear day. The leaf has an emissivity of 0.85 and a specific heat of $0.80\,kcal/kg\,\cdot K$.
(a) Estimate the rate of rise of the leaf’s temperature.    $C^{\circ} $
(b) Calculate the temperature the leaf would reach if it lost all its heat by radiation to the surroundings at 20$^{\circ} $C.    $^{\circ}C $
(c) In what other ways can the heat be dissipated by the leaf?

  Using the result of part (a) m. (onmqn*io15 ekf1m in Problem 58, take into account radiation from the leaf to calculate how much water must be transpired (evaporated) by the leaf per hour to maintain a temperature of*ifo 5.omkmnne 11 q(m 35$^{\circ} C$.    g/h

  An iron meteorite melts when i) /kcd3/e oqhct enters the Earth’s atmosphere. If its initial temperatur/e)hcdq c 3ko/e was -125$^{\circ} C$ outside of Earth’s atmosphere, calculate the minimum velocity the meteorite must have had before it entered Earth’s atmosphere.    m/s

  The temperature within the Earth’66rgpw5uq bv; s crust increases about 1.0 C$^{\circ} $ for each 30 m of depth. The thermal conductivity of the crust is $0.80\,W/C^{\circ} \cdot\,m$
(a) Determine the heat transferred from the interior to the surface for the entire Earth in 1 day.    $ \times10^{18 }\,J$
(b) Compare this heat to the amount of energy incident on the Earth in 1 day due to radiation from the Sun.$Q_{Sun}$ =    $ \times10^{4 }\,Q_{interior}$

  In a typical game of squash (Fig. 14–22), twnjrsi 4b gl(md,s(3 p+o people hit a soft rubber ball at a wall until they are about to drop due to dehydration and ex pg4+ sib3(jnsml,d(rhaustion. Assume that the ball hits the wall at a velocity of $22\,m/s$ and bounces back with a velocity of $12\,m/s$ and that the kinetic energy lost in the process heats the ball. What will be the temperature increase of the ball after one bounce? (The specific heat of rubber is about $1200\,J/kg\,$$\cdot\,C$)    $C^{\circ} $

What will be the final result 1mq +,na9gc gxwhen equal masses of ice at 0$^{\circ} C$ and steam at 100$^{\circ}C $ are mixed together?

  In a cold environment,cg fhpdka:0 oy5n2n4 6 a person can lose heat by conduction and radiation at a rate of about 200 W. Estimate how long it would take for the bnc6:han4kyg025pfo d ody temperature to drop from 36.6$^{\circ} C$ to 35.6$^{\circ} C$ if metabolism were nearly to stop. Assume a mass of 70 kg. (See Table 14–1.)    s

  After a hot shower and dishwashing, there is “no hot water” left in the:)f ib y qz:fahn2ppt so,5dmg98reoi4.x,2 q 50-gal (185-L) water heitm4,822n9d oe5 sf):, g.foppby:hqqza rixater. This suggests that the tank has emptied and refilled with water at roughly 10$^{\circ} C$. (a) How much energy does it take to reheat the water to 50$^{\circ} C$? (b) How long would it take if the heater output is 9500 W?    s

  The temperature of the glass surface of a 60-W lightbulb i3 aafkc1 v*ip4rx 6+jrs 65$^{\circ} C$ when the room temperature is 18$^{\circ} $C. Estimate the temperature of a 150-W lightbulb with a glass bulb the same size. Consider only radiation, and assume that 90% of the energy is emitted as heat.    $^{\circ} C$